Social network Tumblr has asked its users to change their passwords in the emergence of a recent virus called Heartbleed, that has been exposing world's major websites to theft by hackers.

Tumblr said in a statement that the little lock icon (HTTPS) trusted by all to keep their passwords, personal emails, and credit cards safe, was actually making all that private information accessible to anyone who knew about the exploit.

This virus (Heartbleed), which represents one of the most serious global security flaws revealed in recent years, makes possible for hackers to retrieve code from websites that would give them access to other information, including user data and passwords.

Tumblr is trying hard to persuade users to take precautionary measures, the Website added that this might be a good day to call in sick and take some time to change passwords everywhere — especially high-security services like email, file storage, and banking, which may have been compromised by this virus.

While Tumblr claimed that it had taken measures to fix the security flaw, the company said that it had no proof to back its claim that its user data had been breached.